NCT06435429 · Jazz Pharmaceuticals
A Study Comparing the Efficacy and Safety of Zanidatamab to Trastuzumab, Each in Combination With Physician's Choice Chemotherapy, for the Treatment of Participants With Metastatic HER2-positive Breast Cancer
What this study is about
The effectiveness and safety of zanidatamab in combination with physician's choice of chemotherapy compared with trastuzumab in combination with physician's choice of chemotherapy will be evaluated for the treatment of participants with metastatic HER2-positive breast cancer who have progressed on, or are intolerant to, previous T-DXd treatment.
View original scientific description
The efficacy and safety of zanidatamab in combination with physician's choice of chemotherapy compared with trastuzumab in combination with physician's choice of chemotherapy will be evaluated for the treatment of participants with metastatic HER2-positive breast cancer who have progressed on, or are intolerant to, previous T-DXd treatment.
Interventions
DRUG
Zanidatamab
Administered by intravenous infusion
DRUG
Trastuzumab
Administered by intravenous infusion
DRUG
Eribulin
Administered by intravenous infusion
DRUG
Vinorelbine
Administered by intravenous infusion
DRUG
Gemcitabine
Administered by intravenous infusion
DRUG
Capecitabine
Given orally
Primary outcome measures
Progression-free Survival (PFS) Per RECIST Version 1.1 As Assessed by Blinded Independent Central Review (BICR)
Time frame: Until disease progression or death, up to approximately 44 months
PFS is defined as the time in months from randomization to the date of first documented disease progression (as assessed by BICR according to RECIST v1.1) or death from any cause, whichever occurs first.
Who can participate
This study lists these criteria on ClinicalTrials.gov. A study coordinator reviews eligibility during screening — this page does not determine whether you qualify.
Inclusion criteria
- of a woman with an early undetected pregnancy.
- Is capable of giving signed informed consent, which includes compliance with the requirements and restrictions listed in the informed consent form and in the protocol. Participants are excluded from the study if any of the following criteria apply: Medical Conditions
- Has clinically confirmed leptomeningeal disease, in the opinion of the investigator.
- Has uncontrolled or significant cardiovascular disease.
- Has toxicity related to prior cancer therapy that has not resolved to ≤ Grade 1, with exceptions as stated in the protocol.
- Has uncontrolled infection requiring IV antibiotics, antivirals, or antifungals.
- Has an infection with HIV-1 or HIV-2, with the exception of participants with well-controlled HIV.
- Has active hepatitis B or C infection.
- Has an active SARS-CoV-2 infection. Participants with prior infection that has resolved per local institutions' requirements and screening guidance are eligible.
- Has a history of life-threatening hypersensitivity to monoclonal antibodies or to recombinant proteins or excipients in the drug formulation of zanidatamab.
- Is unable to receive trastuzumab treatment due to medical contraindications.
- Has any serious underlying medical or psychiatric condition that would impair the ability of the participant to receive or tolerate the planned treatment at the investigational site.
- Has any condition that would prevent treatment with the physician's choice of chemotherapy.
- Has any issue or condition that in the opinion of the investigator would contraindicate the participant's participation in the study or confound the results of the study. Prior/Concomitant Therapy
- Has a history of prior allogeneic bone marrow, stem cell, or solid organ transplantation.
- The washout periods for prior anticancer therapies before randomization as specified in the protocol.
- Has a history of trauma or major surgery within 4 weeks prior to randomization. Other
Exclusion criteria
- Has a known hypersensitivity to any components of the study drugs, including chemotherapy.
- Female participants who are breastfeeding or pregnant, and female and male participants planning a pregnancy.
Where
- Phoenix, Arizona
- Tucson, Arizona
- Cerritos, California
- Glendale, California
- Los Angeles, California
- San Francisco, California
- Aurora, Colorado
- Denver, Colorado
- Washington D.C., District of Columbia
- Fort Myers, Florida
- Jacksonville, Florida
- St. Petersburg, Florida
And 25 more locations — see the full list below.
Related conditions & keywords
Frequently asked questions
What is a clinical trial?
A clinical trial is a research study that tests new medical treatments, drugs, devices, or procedures to determine their safety and effectiveness. Trials are carefully designed and monitored to protect participants while advancing medical knowledge.
Is it safe to participate?
Clinical trials follow strict safety guidelines and ethical standards. Trials must be reviewed and approved, and participants are closely monitored by medical professionals throughout the study. You can withdraw at any time if you choose.
Will I be compensated?
Many clinical trials offer compensation for your time, travel expenses, and inconvenience. The specific compensation varies by study and will be discussed during the screening process. All study-related medical care is typically provided at no cost to participants.
Will I receive a placebo instead of treatment?
When effective treatment exists, participants typically receive either the standard treatment plus the study intervention, or the standard treatment plus placebo. You would not be denied effective care. Placebos are primarily used when no proven treatment is available, or in addition to standard care. Your trial consent form will clearly explain what treatments you may receive.
Can I leave a trial if I change my mind?
Absolutely. Participation in clinical trials is completely voluntary. You have the right to withdraw from the study at any time, for any reason, without penalty or loss of benefits to which you are otherwise entitled.
How long does a clinical trial last?
Trial duration varies widely depending on the study design and purpose. Some trials last just a few weeks, while others may continue for months or years. The study coordinator will provide specific timeline information during your screening call.
Data: ClinicalTrials.gov · synced Feb 10, 2026 · Source of record for eligibility and locations